Electric-switch-contact holder.



D. LARSON.

ELEGTRIG SWITCH CONTACT HOLDER.

APPLICATION FILED MAY 7, 1908.

1,016,833, Patented Fb.6,1912.

anus/1 1 q/vi-l 14000.00

UNITED STATES PATENT OFFICE.

DAVID LARSON, OF YONKERS, NEW YORK, ASSIG-NOR '10. OTIS ELEVATORCOMPANY,

OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY. I

ELECTRIC-SWITCH-CONTACT HOLDER.

Specification of Letters Patent.

Patented Feb. 6, 1912.

To all whom it may concern:

Be it lmown that 1, DAVID LARSON, a subject of the King of Sweden,residing at Yonkers, in the county of Westchester and State of New York,have invented a new and useful Improvement in Electric-Switch- ContactHolders, of which the following is a specification. I

My invention relates to electric switches, and one of its objects is theprovision of an improved yielding contact holder.

Another, object of the present invention is the provision of an improvedfixed contact holder.

Other objects of the invention will appear hereinafter, the novelcombinations of elements being set forth in the appended claims.

Referring to the accompanying drawings, Figure 1 is a part sectionalside elevation of an electric switch embodying my invention; Fig. 2 is afront elevation on an en larged scale of a portion of Fig. 1; and Fig. 3is a sectional view of the stems of the clamping jaws.

The invention is adapted to beapplied to various forms of switches, bothmanual and automatic, but as it involves features that specially adaptit for use with switches operated by alternating current magnets, I haveshown the invention embodied in a switch of this kind. To a baseor-support 1 of slate or other insulating material is secured a bracket2, to which is pivoted at 3 the switch arm 4. The, outward movement ofthe arm 4 is limited by a stop 5 in the path of movement of an extension6 of the switch arm. An el'ectromagnet comprising a laminated frame 7and a winding 8 is secured to the base 1, and its armature 9 is securedto the switch arm 4. A coil spring 10 surrounds a rod 11 which ispivoted at one end to the arm 4 and extends loosely through an openingin the base plate 1.

This spring serves to open the switch when the magnet is deenergized.

The switch arm 4 carries a movable contact 12 in the form of a flat.plate or disk having a stem 13, preferably rectangular or irregular incross section, extending through the switch arm; The movable contact isinwasher 17 bearing against the washer 16 and the end of the sleeve 14..The outer end 18 of the stem 13 is circular in cross-section andthreaded to receive the nuts 19, 20 and 21. A metallic washer 22 isplaced between the washer 17 and the-nut 19, a terminal 23 of anelectric conductor is clamped between the nuts 19 and 20, and a lock nut21 is curely in position on. the contact stem so that they will movewith the contact 12.

The sleeve 24 extends loosely through an opening 42 in the switch armand is yieldingly held in its forward position by a coil spring 27 whichbears against the flange 25 and the rear end of which lies in a recess28 formed in the switch arm. As the switch arm moves forward toward itsclosed position, the contact 12 engages the stationary contact 30 beforethe switch arm has reached its forward limit of movement, and thecontinued movement of the switch arm compresses the spring 27 and holdsthe switch contacts together with a yielding pressure. The spring 27serves to hold the flat surfaces of the contacts 12 and 30 squarely inengagement with each other when the armature is in attracted position,as there is sufficient clearance between the sleeve 24 and the switcharm 'at the opening 42 to permit a slight angular movement of thecontact 12 in any direction which may be necessary to make the contactsurfaces parallel. The insulation prevents the spring 27 from becomingheated to such a temperature that its resiliency is destroyed and themetal I sleeve 14 and metal washer 26 take up wear.

The stationary contact 30 consists of a carbon block held betweenclamping jaws 31 and 32. The jaw 31 is formed with a stem 33 extendingthrough the base 1 and having a threaded portion 34 extending be- .yondthe base and forming a binding post for a conductor which may be clampedbetween the nuts 35 and 36. The nut 35 also serves to clamp the jaw 31rigidly to the base, a washer 37 being placed between the nut 35 and thebase. The movable clamping jaw 32 is provided with a stem 38 extendinginto the base 1 with its end abutting against a shoulder 39 formed onthe stem 33. As shown in Fig; 3, the stems of the clamping jaws are bothsubstantially semi-circular in cross-section, with their fiat surfacespar= allel and spaced a short distance apart. The end of the stem 38 isprovided with a V- shaped projection 40 which engages a notch 41 in thestem 33 and forms 'a knife bearing permitting a rocking movement of thejaw 32 to insure good electrical contact between the clamping jaws andthe carbon block 30. A screw 42 which passes freely through the bodyportion of the jaw 31 and is threaded into the body portion of the jaw32, serves to clamp the jaws tightly against the carbon contact. 7 I

The jaw 31 with its stem 33-and end 34 'is preferably a single castingso that the only machining required is the threading of the end 34, thehole for the bolt 42 being formed when the jaw is cast. Thisconstruction permits the use of material like aluminumbronze which is agood conductor of electricity, but is hard andhnyielding. The jaw 32 ismade of brass or bronze, or any other suitable elastic or springymaterial, but not necessarily a good conductor of electricity. The jaw31being made of good conducting material, is suflicient to carry the,current with little' loss of energy or heating, while the elastic jaw32 maintains 3 a good contact between the carbon 30 and jaw 31 through awide range of temperaturesa Thecarbon when it becomes heated does notexpand as much as the metal, and.

parts and materials used as might be made by those skilled in the artwithout departing from the spirit and scope of the invention as definedin the appended claims. I wish therefore not to be limited to theprecise construction disclosed.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is 1. In a switch, the combination with asupport formed with anopening therein, of

a pair of clamping jaws each having a stem extending into said opening,and means for securing the jaws together.

2. In a switch, the combination with a support, of a clamping jaw havinga stem extending through an opening in the support, a threaded extensionon the stem, a clamping nut on said extension, a second clamping jawhaving a stem extending into said opening, and means for clamping saidjaws to a switch contact.

In testimony whereof, I have signed my name to thisspecification in thepresence of two subscribing witnesses.

Witnesses:

CHAS. M. NIssEN, JAMES D. 'IvERs.

DAVID LARSON.

